In surveying, the use of a camera in a geodetic instrument may provide for improved user convenience and new functions. Particularly, a view such as an image or a video feed provided by the camera and shown on a display of the instrument may be used for assisting target selection and for providing the user with an overview of potential points of interest.
One apparent difference between a traditional eyepiece and a video image shown on a display, is that the display image may have an active overlay of information. Various information may be given together with the captured image to facilitate instrument usage.
For a general background of a geodetic instrument comprising a camera for capturing an image or a video feed of the view towards which the geodetic instrument is aimed, reference is made to WO 2005/059473.
Surveying instruments of this kind, i.e. which includes a camera, are sometimes referred to as video-theodolites.
In a conventional geodetic instrument, electronic distance measuring (EDM) may alternatively or additionally be used, where a modulated light beam is emitted towards a target, and light reflected against the target is subsequently detected at the geodetic instrument.
Processing of the detected signal enables determination of distance to the target by means of e.g. time of flight (TOF) measurements or phase modulation techniques. Using a TOF technique, the time of flight of a laser pulse from the geodetic instrument to a target and back again is measured and distance can thus be calculated. Using a phase modulation technique, light of different frequencies is emitted from the geodetic instrument to the target, whereby reflected light pulses are detected and the distance is calculated based on the phase difference between emitted and received pulses.